Patients throughout the state of Kansas who are taken to surgery because of a breast mass will have a serum sample drawn prior to surgery, one week after surgery and one month after surgery. These serum samples will be sent to the University of Kansas Medical Center where they will be tested in immunodiffusion and complement fixation for antibody to a breast cancer antigen. This part of the program is completely administered by a computer, including the dissemination of letters requesting serum samples, data, etc. Those patients at KUMC who have carcinoma of the breast will be studied more thoroughly for their immunologic responsiveness by appropriate skin testing, as well as for phagocytic index.